Project Abstract Emergency medicine developed as a specialty to treat the acutely ill and injured, but increasingly cares for older adults with multiple comorbid conditions. An Emergency Department (ED) visit is a sentinel event for older adults, often signifying a breakdown in care coordination and worsening clinical and functional status. Half of Americans 65 years and older are seen in the ED in the last month of life, and three-quarters visit the ED in the 6 months before death. Meanwhile, the number and rate of admissions to the Intensive Care Unit (ICU) by emergency providers have been increasing, especially among older adults. Three-quarters of older adults with serious illness have thought about end-of-life care, and only 12% want life-prolonging care. Emergency providers impact a patient's clinical trajectory by balancing the potential harms and benefits of hospitalization and connecting seriously ill, older adults with outpatient services. Until recently, little attention has been paid to aligning care plans with patient goals for older adults in the ED. To address this gap in the delivery of goal-directed emergency care of seriously ill, older adults, our team conducted a randomized controlled trial of ED-initiated palliative care consultation in advanced cancer that showed improvement in quality of life at 12 weeks. We also showed in a Center for Medicare and Medicaid Innovation project that ED- based primary palliative care innovations reduced the percentage of geriatric ED admissions to the ICU from 2.3% to 0.9% through screening for high-risk older adults, early referral to palliative care and hospice, and emergency provider training and education in palliative care principles. Whether this approach will be feasible and effective in EDs with great heterogeneity in resources is unknown. We will tailor `primary palliative care for emergency medicine' (PRIM-ER) for implementation in a diverse group of 35 EDs that vary in specialty geriatric and palliative care capacity, geographic region, payer mix, and demographics. This proposal builds upon existing research partnerships to implement and evaluate PRIM-ER on ED disposition, healthcare utilization, and survival in older adults with serious, life-limiting illness. Our hypothesis is that older adult visitors with serious, life-limiting illness cared for by providers with primary palliative care skills will be less likely to be admitted to an inpatient setting, more likely to be discharged home or to a palliative care service, and will have higher home health and hospice use, fewer inpatient days and ICU admissions at 6 months, and longer survival than those seen prior to implementation. We propose a pragmatic, cluster-randomized stepped wedge design to test the effectiveness of PRIM-ER in 35 EDs. PRIM-ER includes: 1) evidence-based, multidisciplinary primary palliative care education, 2) simulation-based workshops on communication in serious illness, 3) clinical decision support, and 4) provider audit and feedback. The specific aims are divided into a: 1) UG3 Phase, in which we will tailor the protocols to a diverse ED context and pilot test the intervention at two sites; and a 2) UH3 Phase in which we will test the intervention in a stepped wedge design in 33 EDs.